Republican presidential candidate Rick Santorum is out with a hard-hitting new ad targeting rival contender Herman Cain on the issue of abortion.

"Now, the most troubling news of all is Herman Cain's newly-discovered pro-choice position on abortion," a narrator says in the spot, after briefly taking aim at the former Godfather's Pizza CEO on fiscal issues. "And Cain's announcement of his pro-choice position certainly hasn't gone unnoticed. Pro-life leader Alan Keyes called Cain pro-choice and said Herman Cain's position is the same postion taken by abortion-rights Democrats like Hillary Clinton. Conservative leader Steve Deace described Cain's position as favoring baby-murder in cases of rape and incest."

"It's not the government's role or anybody else's role to make that decision," Cain responded when asked to address the issue applied to a hypothetical rape case. "Secondly, if you look at the statistical incidents, you're not talking about that big a number. So what I'm saying is it ultimately gets down to a choice that that family or that mother has to make."

Cain sought to do damage control on the comments shortly after during an appearance on Fox News. He explained, "Abortion should not be legal, that is clear. But if that family made a decision to break the law, that's that family's decision, that's all I'm trying to say."

Earlier this week, however, Cain said he doesn't believe abortion should be part of the political discussion. "But my position is real clear and has been consistent, I am pro-life," he said.

The attack ad from Santorum's campaign features footage of remarks from Cain defining his stance on the issue. "The more we learn, the more concerned we become," the spot concludes.

It's not the first time Santorum has pounced on Cain on abortion. "As the author of the legislation that banned partial birth abortions forever, I am stunned that someone running for the Republican nomination for president would have this position," the former senator recently said in a statement. "In fact, Herman Cain's pro-choice position is similar to those held by John Kerry, Barack Obama and many others on the liberal left. You cannot be both personally against abortion while condoning it -- you can't have it both ways. We must defend the defenseless, period."